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Everyone’s favourite clownfish is back, but this time, he’s in 3D! With the beloved movie Finding Nemo returning to theatres this weekend, I thought it would be fun to do a little research on our friend, Nemo.
Everyone who has watched the movie knows that Dory is a forgetful fish, but few people know that Nemo, the clownfish, can potentially be a deaf fish. Recent studies have shown that clownfish are quickly losing their hearing due to ocean acidification caused by fuel emission. In fact, over half the CO2 emission is absorbed by the ocean, thus lowering its pH. In this experiment, scientists performed a series of tests by increasing the amount of CO2 to what is predicted to be present in years 2050 and 2100, and then recorded the clown fish’s response to various predator-rich coral reef sounds.
Graph of CO2 consumption and pH levels of oceans as a function of time http://centerforoceansolutions.org/climate/wp-content/uploads/2009/12/Acid_pH_graph.jpg
Lead researcher Dr Steve Simpson from the University of Bristol explains: ‘We kept some of the baby clownfish in today’s conditions, bubbling in air, and then had three other treatments where we added extra CO2 based on the predictions from the Intergovernmental Panel on Climate Change for 2050 and 2100. We designed a totally new kind of experimental choice chamber that allowed us to play reef noise through an underwater speaker to fish in the lab, and watch how they responded. Fish reared in today’s conditions swam away from the predator noise, but those reared in the CO2 conditions of 2050 and 2100 showed no response.’
For baby clownfish such as Nemo, their ability to hear is one of their most important assets in ocean survival; with this component slowly being stripped from them, they are becoming increasingly vulnerable to predators. Not only is hearing a sense of protection, clownfish and other coral reef species also rely on their hearing to return home. To make matters worse, ocean acidification does not only affect external matters, it can damage the inside of the fish as well.
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The future of these clownfish’s hearing may be bleak , but scientists have yet to find out if they will adapt to the change in water pH. At the moment, this research is done one way; therefore there is a chance that clownfish can evolve and maintain their hearing.
Blog post submitted by: Deborah Lo
References:
Daily Mail: “Finding deaf Nemos: Clownfish are growing up with impaired hearing ’caused by fossil fuel emissions.'” – http://www.dailymail.co.uk/sciencetech/article-1393045/Finding-deaf-Nemos-Clownfish-growing-impaired-hearing-caused-fossil-fuel-emissions.html (accessed September 13, 2012)
University of Bristol: “Ocean acidification makes clownfish hard of hearing.” – http://cordis.europa.eu/fetch?CALLER=EN_NEWS&ACTION=D&RCN=33485 (accessed September 14, 2012)
